1. Field of the Invention
The present invention relates to an apparatus for extracting pitch data from an input waveform signal, and an electronic device for generating a musical tone having a tone pitch corresponding to the extracted pitch data and, more particularly, to an electronic stringed instrument such as an electronic guitar or a guitar synthesizer.
2. Description of the Related Art
Various apparatuses for extracting data representing a pitch (fundamental frequency) from an waveform signal generated in accordance with a human voice or performance of a conventional instrument, and controlling a sound source apparatus constituted by an electronic circuit to artificially obtain sounds such as a musical tone are recently developed.
These techniques are disclosed in the following publications.
USP No. 4,117,757 (issued on Oct. 3, 1978) PA1 Inventor: Akamatsu PA1 USP No. 4,606,255 (issued on Aug. 19, 1986) PA1 Inventors: Hayashi et al. PA1 USP No. 4,633,748 (issued on Jan. 6, 1987) PA1 Inventors: Takashima et al. PA1 USP No. 4,688,464 (issued on Aug. 25, 1987) PA1 Inventors: Gibson et al. PA1 Japanese Patent Publication No. 57-37074 (published on Aug. 7, 1982) PA1 Applicant: Roland K.K. PA1 Japanese Patent Publication No. 57-58672 (published on Dec. 10, 1982) PA1 Applicant: Roland K.K. PA1 Japanese Patent Disclosure (Kokai) No. 55-55398 (disclosed on Apr. 23, 1980) PA1 Applicant: TOSHIBA CORP. PA1 Japanese Patent Disclosure (Kokai) No. 55-87196 (disclosed on July 1, 1980) PA1 Applicant: Nippon Gakki Co., Ltd. PA1 Japanese Patent Disclosure (Kokai) No. 55-159495 (disclosed on Dec. 11, 1980) PA1 Applicant: Nippon Gakki Co., Ltd. PA1 Japanese Utility Model Disclosure (Kokai) No. 55-152597 (disclosed on Nov. 4, 1980) PA1 Applicant: Nippon Gakki Co., Ltd. PA1 Japanese Utility Model Disclosure (Kokai) No. 55-162132 (disclosed on Nov. 20, 1980) PA1 Applicant: Keio Giken Kogyo K.K. PA1 Japanese Patent Publication No. 61-51793 (published on Nov. 10, 1986) PA1 Applicant: Nippon Gakki Co., Ltd. PA1 Japanese Utility Model Publication No. 62-20871 (published on May 27, 1987) PA1 Applicant: Fuji Roland K.K. PA1 Japanese Patent Disclosure (Kokai) No. 61-26090 (published on Feb. 5, 1986) PA1 Applicant: Seiko Denshi Kogyo K.K. PA1 Japanese Patent Disclosure (Kokai) No. 62-163099 (disclosed on July 18, 1987) PA1 Applicant: Fuji Gengakki Seizo K.K.
In addition, Uchiyama et al. filed U.S. patent applications each disclosing a system associated with the present invention (USSN 112,780 on Oct. 22, 1987, and a new U.S. Patent application filed on Oct. 3, 1988).
In such a prior art, in particular, an electronic guitar (guitar synthesizer) with a tremolo arm can extremely change a tone pitch of a string during tone generation.
In electronic instruments of this type, since a tremolo unit is vibrated by picking of the strings, the tone pitch just after picking is unstable. Therefore, after tone generation is started using a first extracted pitch, the tone pitch is undesirably kept continued until the next pitch is extracted. As a result, the tone pitch of the musical tone generated from a sound source is out of tune as compared to an actual acoustic sound.
Therefore, a musical performance discomforts listeners since actual tone pitches are deviated from the designated pitches.